Project Summary The voice is integral to human communication, yet over 7.5 million people in the United States report difficulty with their voices. Individuals with voice disorders may experience physical or emotional stress, and an overall decreased quality of life as a consequence of the disorder. The direct health-care costs for the diagnosis and treatment of these voice disorders are estimated at $11.9-$13.5 billion annu- ally. Unfortunately, an estimated 28,000 Americans are dependent on their voices for their profession. The vocal demands of these occupational voice users increase not only the individual?s risk for develop- ing vocal pathologies, but also the professional and socioeconomic consequences of developing such a disorder. Thus, voice disorders are a significant public health concern and an area of high importance to the National Institute on Deafness and Other Communication Disorders (NIDCD). The current research plan aims to determine the impact of phonotrauma on laryngeal function using an established in vivo rabbit phonation model. Aim 1 will investigate how normal laryngeal function changes in response to increased time-doses of raised intensity phonation. Aim 2 will extend the investigation to include measurement of the recovery of normal vibratory function after phonotrauma. Together, these aims will investigate the development of vibratory irregularities and recovery of laryngeal function after acute phonotrauma. The significance of the proposed research plan is that it will provide physiologic data to determine (a) the effects of phonotrauma on functional tissue outcomes, and (b) the effects of increased magnitude-doses of vibration exposure on recovery of normal vibratory function after phonotrauma. If the aims are accomplished, these findings will be used to provide empirical data to support recommen- dations regarding voice use and profiles of normal tissue recovery.